The issue rocked Canadian politics starting in 2007 and threatened to topple Prime Minister Stephen Harper's minority government in late 2009, a fate the Conservatives avoided by shutting down Parliament.
The Military Police Complaints Commission, in a long-awaited report, concluded the officers had no grounds to open an investigation into the treatment of suspected Taliban prisoners after they were handed over to local authorities in Kandahar.
But the watchdog agency noted the police were kept out of the loop by the Ottawa-based overseas command that ran the war, saying the headquarters did not share critical information and warnings that might have prompted an investigation.
The complaint was laid in 2007 by two human rights groups, Amnesty International Canada and the B.C. Civil Liberties Association, both of which tried and failed through the courts to halt the transfer practice.
None of the eight military police officers named in the complaint ever received a direct report of torture inside Afghan jails, the report said.
The commission was barred by a court order from finding criminal liability or possible criminal liability. It had the latitude to say whether anyone failed in their duty.
The agency ripped into the Harper government for blocking access to witnesses and documents and presenting “an overall attitude of antipathy…towards the commission and its task."
Peter Tinsley, the former commission chair who ordered the inquiry, said it was evident to him the obstruction was not meant to protect the soldiers accused of wrongdoing.
"I'm troubled by the duplicity," said Tinsley. "I don't think it was the interests of those individuals, who were the subjects of the inquiry, the representation of their interests, that caused the government to throw-up the roadblocks. It was a government interest."
Tinsley is a former military prosecutor and an international war crimes prosecutor who once ran for the Commons as a Liberal.
Opposition critics condemned the government for its handling of the issue
NDP Foreign Affairs critic Paul Dewar said the government stonewalled efforts to get to the bottom of the matter:
"This is a commission of inquiry that was set up by government, to do what? To provide transparency and accountability, and all they've done is fog the windows on transparency and accountability and hope that nobody's going to notice."
Liberal defence critic John McKay said the government tried to protect itself.
"Rather than providing the information the commission needed to clear the soldiers, in a timely manner, Prime Minister Harper yet again chose to look after Prime Minister Harper, leaving the soldiers on their own," McKay said.
The exhaustive report, which runs to 571 pages, was released just days after Parliament recessed for the summer, giving MPs no opportunity to debate the report or question the government until they return in mid-September.
The report did find there was a "great deal of reliable information," both public and classified, that documented the risk of mistreatment once prisoners were handed over to Afghan authorities.
"The commission discovered in the course of its proceedings that key information with respect to detainee abuse, and in particular the site-visit reports from (the Department of Foreign Affairs), tended to stay within a closed circle of individuals at (Canadian Expeditionary Forces Command)."
That circle included the general in charge at the time, his chief of staff and close advisers.
The top military police adviser at the headquarters was also kept out of the loop by not having access to reports filed by diplomats who visited Afghan prisons.
When the officer asked about circumstances that led the army to halt transfers in November 2007: "He was told he did not have a 'need to know' the details of those detainee discussions."
Warnings about conditions within the Afghan prison system by diplomat Richard Colvin, made directly to the headquarters' policy adviser during an Ottawa meeting in early 2007, were not passed along.
Both Amnesty and the civil liberties association began sounding warnings about conditions in Afghan prisons in late 2005 when Canada decided to transfer prisoners captured during the combat mission to local authorities, rather than the U.S.
The lawyer for the human rights groups said his clients were disappointed by the findings.
"There is no justice here for the many prisoners who were transferred from Canadian custody into the hands of torturers," Paul Champ said in an email.
He said the commission's mandate was flawed and the issue will be left to fade away.
"The commission did make it clear that there was significant evidence about the risk of torture to the detainees," said Champ.
"While the commission did make recommendations about the military police chain of command, the most important lessons to be learned aren't found in this report. The commission suggests that 'others' will be left to consider whether the right decisions were made, but there are no other processes available for that."
Given the way the Harper government "obstructed and delayed" the commission's investigation, the secretary general of Amnesty International Canada said he's not sure the public will ever get the full story of what went on in Afghanistan.
"The government has made it clear that they do not invite or welcome scrutiny of that nature when it comes to detainee transfers," Alex Neve said in a statement.
A spokesman for Defence Minister Peter MacKay expressed satisfaction with the report, noting that the commission concluded soldiers and military police "acted in a professional manner."
"This report is one more investigation demonstrating that no credible evidence was found to support the allegations against our men and women in uniform," said Joshua Zanin, adding that the government has "taken note" of the commission's recommendations.
"The men and women of the Canadian Forces who have and continue to serve in Afghanistan put their lives on the line every day. We are proud of their professionalism in the conduct of the work we ask them to do. "
Under international law, Ottawa was obliged to insure detainees did not face the risk of torture. The agreement with the Afghan government did not give Canadian authorities an automatic right to check on the condition of those who were transferred.
That changed in the spring of 2007 when allegations of abuse of Canadian-captured prisoners hit the front page of the Globe and Mail. Diplomats began follow-up visits, which continued until the end of the combat mission last year.
The commander of CEFCOM, now-retired lieutenant-general Michel Gauthier, ordered a National Investigative Service probe of the newspaper story, which also might have led to a military police investigation.
But the commission said the NIS conducted only a cursory review of the allegations contained in the article and the agency was unaware that a separate headquarters' analysis of the story had identified some of the people who claimed to have been tortured.
"Not a single external source of information was considered or reviewed ... It appears the investigators never considered whether the orders to transfer may have been illegal and worked on the presumption that if anyone had behaved illegally, it was solely the Afghan authorities."
When the commission decided to hold public hearings into the complaint, the Harper government went to court to try to stop it, arguing the agency didn't have jurisdiction.
The Federal Court decided the probe could take place, but only within the confines of what the military police knew or should have known about alleged torture.